ZyXEL NAS540 User Guide - Page 66

Chapter 4 Web Configurator Basics Table 20 S.M.A.R.T. Attributes (continued) ID ATTRIBUTE NAME BETTER DESCRIPTION 09 Power-On Hours Low (POH) This is how many hours the hard drive has been in a power-on state. The raw value lists the total number of hours (or minutes, or seconds depending on the manufacturer). 10 Spin Retry Count Low This is the total number of spin start retry attempts. This is the number of attempts to spin up to fully operational speed the hard drive has made when the first attempt did not succeed. An increase in this value is an indicator of hard disk mechanical subsystem problems. 11 Recalibration Retries High This is the number of times recalibration was requested when the first attempt did not succeed. A decrease in this value is an indicator of hard disk mechanical subsystem problems. 12 Device Power Cycle Count This is the number of times the hard drive has gone through a full power on and power off. 13 Soft Read Error Low Rate This is the number of uncorrected read errors the hard drive has reported. If this is not zero, back up your data. 190 Airflow Low Temperature This indicates the temperature of the airflow measured by a Western Digital hard drive. 190 Temperature Difference from 100 High This indicates the value of 100 - the temperature in degrees Celsius. Manufacturers can set a minimum threshold that corresponds to a maximum temperature. 191 G-sense error Low rate This is the number of mistakes caused by impact loads. 192 Power-off Retract Low Count This is how many times the heads are loaded off the media. 193 Load/Unload Low This is the number of load and unload cycles into head landing zone Cycle position. 194 Temperature Low This is the hard drive's internal temperature. 195 Hardware ECC Recovered High This is the time between ECC (Error Correction Code)-corrected errors. 196 Reallocation Low This is the total number of reallocation (remap) operations. The raw value Event Count is the total attempts to move data from reallocated sectors to a spare area. Successful and unsuccessful attempts are both included. 197 Current Pending Low Sector Count This is the number of unstable sectors awaiting reallocation. If the sector is later successfully written or read, this value decreases and reallocation is not performed. Only failed write attempts cause a reallocation, not read errors. This can be difficult to test since only direct I/O writes to the disk cause reallocations, not cached writes. 198 Uncorrectable Low Sector Count This is the number of errors reading or writing a sector that were not correctable. An increase in this value is an indicator of disk surface defects or mechanical subsystem problems. 199 UltraDMA CRC Low Error Count This is the number of data transfer errors through the interface cable according to the ICRC (Interface Cyclic Redundancy Check). 200 Write Error Rate Low / Multi-Zone Error Rate This is the total number of errors in writing sectors. 201 Soft Read Error Low Rate This is the number of read/write head off-track errors. If the value is not zero, make a backup. 202 Data Address Low Mark Errors This is the number of data address mark errors. This could also be a different, manufacturer-specific attribute. 203 Run Out Cancel Low This is the number of ECC (Error Correction Code) errors. 66 NAS540 User's Guide